Molecule-responsive fluorescent sensors of α-helix peptides bearing α-cyclodextrin, pyrene and nitrobenzene units in their side chains

Abstract

α-Helix peptides bearing one unit of α-cyclodextrin (α-CD), one unit of pyrene and one unit of nitrobenzene (NB) in their side chains have been designed and synthesized as novel molecule-responsive devices. In both the CD-peptides, α-PR17 and α-PL17, the NB unit is separated from the CD unit by two turns of the helix. Two reference peptides (PR17 and P17) have also been synthesized. The circular dichroism studies in the peptide absorption region (200-250 nm) of α-PR17 and α-PL17 suggest that the CD-peptides form stable α-helix structures (83-77%), which was destabilized by accommodating guest molecules (e.g., n-pentanol) into the CD cavity. It suggests that formation of intramolecular host-g..